The leaching of contaminants from human crop fields, lawns, gardens and parks is a major cause of water resource contamination and pollution. Contaminants of particular concern include, but are not limited to fertilizers, pesticides and pathogenic microorganisms that can leach into water sources e.g., groundwater, rivers, lakes, streams, and estuaries.
Despite the beneficial effects on cultivated plants, when fertilizer nutrients such as nitrogen, potassium, and phosphorus end up in the larger environment, the result is contamination and often eutrophication of water sources e.g., lakes, rivers, streams and estuaries.
Unfortunately, the problem of eutrophication is extensive. Indeed, eutrophication accounts for nearly one half of impaired lake areas in the U.S., and an even greater portion of impaired rivers. Eutrophication is rapidly expanding not only in lakes and rivers, but also in estuaries and coastal seas of the developed world. Thus, fertilizer nutrient runoff leads to eutrophication and upsets the ecological balance. The ecological imbalance can have dangerous consequences, the full extent of which is still unknown.
Pesticide contamination of water resources is also problematic. Insecticides, herbicides, and fungicides which are used to kill agricultural pests, enter the water system and contaminate water resources through both direct application, and runoff. Contaminating pesticides poison fish and wildlife, contaminate food sources, and destroy animal habitat. Furthermore, many pesticides are toxic to human beings, and thus their presence in water supplies poses a significant human health threat.
Unfortunately, agriculture is one of the largest contributors of fertilizer and pesticide pollution. Indeed, agricultural pollution is a major source of water quality impacts to rivers and lakes, the third largest source of impairments to estuaries, and is also a major contributor to groundwater contamination and wetlands degradation. However, agriculture is not the sole contributor to the problem of fertilizer and pesticide contamination of water resources. Indeed, runoff from the maintenance and beautification of parks, lawns, golf courses and gardens are also significant contributors to nonpoint source pollution of water resources.
Currently, the United States has over 330 million acres of agricultural land, between about 14 and 26 million acres of lawn, and between about 2 million to about 3 million acres of golf courses distributed over about 15,827 facilities. The runoff pollution generated from just these sources is significant, and is damaging enough to warrant measures for the reduction of runoff pollution. Indeed, as more native lands are converted for agricultural, recreational, housing and other human development purposes, further increases to nonpoint source pollution of water resources are expected. If these sources of pollution are not controlled, extreme environmental degradation will inevitably result.
Clearly, what is needed are fertilizer and pesticide formulations and methods of their application that reduce or eliminate nonpoint source pollution while maintaining the quality and abundance of American agriculture and the beauty of American home landscapes, recreational facilities and public parks.
Current fertilizer technology consists primarily of direct application and/or slow release fertilizers e.g., Osmocote®, ESN®, Polyon®, and Avail®, to name a few. Unfortunately, slow release fertilizers are designed either to delay release of fertilizer components by holding nutrients in place and then releasing them all at once at some time after the application e.g., by using a water soluble membrane (see e.g., U.S. Pat. No. 6,858,634 U.S. Pat. No. 6,864,245; U.S. Pat. No. 6,900,162; and U.S. Pat. No. 7,018,441). Or in the case of low solubility slow release fertilizers, the composition must rely on natural processes e.g., soil pH, soil temperature, rainfall, etc., to release the fertilizer. Since the majority of nutrients still enter the environment in a short interval of time, the excess that typically results in run-off is still created.
Similarly, current pesticide application methods do little to ensure that the pesticide remains in the place where it is applied. For example, soil insecticides and nematicides are typically either incorporated in the soil, surface applied, and/or applied over-the-top of foliage. Clearly losses will occur in the first few rainfall events after application. Not surprisingly, the situation of environmental pesticide contamination is made more egregious by pesticides that persist longer in the environment, since such long lasting pesticidal chemicals are exposed to more leaching and runoff events.
Thus, the same fertilizers and pesticides that ensure abundant agricultural harvests and attractive yards, parks and recreational facilities are also problematic in that they contribute significantly to the degradation of water supplies through run-off and leaching which produces pollution and eutrophication. Therefore, fertilizer and pesticide formulations and methods of application that minimize pollution while simultaneously preserving the benefits of fertilizers and pesticides are clearly needed in the art. Fortunately, the invention disclosed herein meets these and other needs.